Polish localisation
Added GuardianModelAdminMixin -- fixes #64
Polish translation instead of empty file from 3ab915e48964d9b5a19ccda6cd3ebca78433da6f
Merge branch 'devel' of github.com:nickers/django-guardian into pl-trans
Merged from git@github.com:nickers/django-guardian.git devel
Added Tomasz to authors
Updated changelog
Another changelog update